An examination of the currently fashionable thesis that scientists, and especially biologists in the wake of the Darwinian Revolution, can now solve the problems that traditional philosophers have only talked about. Past philosophers, for example during the Enlightenment, have themselves made use of contemporary, scientific techniques and theories. The present claim may only be another such move, to be welcomed by philosophers who would distinguish themselves from rhetoricians. Others may prefer to stake out the merely human or subjective world as their field, identifying 'truth' with 'what it's better to believe'. Both moderns and postmoderns must abandon the rational realism that actually sustained Enlightenment endeavours, and Darwinian explanation, on its own, must erode traditional ethical values and the meta-ethical assumptions that sustain them. Universal humanism is only one possible project among many - and Darwinian reasonings suggest that it is hypocritical. In this crisis there may after all be a rôle for traditional, Platonizing philosophers, believing that there is a truth, and that we can find it out. Such a theory is actually better able to explain our scientific successes, and our evolutionary past.